JPH0343650Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is used in scanning electron microscopes, etc., by changing the ratio of the scanning width of the electron beam in the horizontal or vertical direction on the specimen, so that the image display means can display the specimen with different magnifications in the horizontal or vertical direction. The present invention relates to a device for displaying a scanned image.

Generally, in a scanning electron microscope, an electron beam is irradiated onto a sample surface, and the electron beam irradiation position on the sample surface is two-dimensionally scanned in the horizontal (X-axis) and vertical (axis) directions. 2. Description of the Related Art There has been provided an apparatus that detects a signal generated from a sample and applies it as a video signal to a synchronized cathode ray tube, thereby enlarging and displaying a sample image.

Incidentally, these devices include an X-axis deflection coil and a Y-axis deflection coil as electron beam deflection means for two-dimensionally scanning the electron beam on a sample surface, and a scanning signal that supplies a deflection signal to the electron beam deflection means. It is provided with a generating means, and supplies the output signal from the scanning signal generating means to the X-axis deflection coil and the Y-axis deflection coil via a magnification control circuit (current control circuit). Furthermore, the output signal from the scanning signal generating means is also supplied to deflection coils X and Y in the cathode ray tube that displays the video signal, and the electron beam scanning in the cathode ray tube is synchronized with the electron beam scanning on the sample surface. Therefore, if a detection signal from the sample is applied to the brightness modulation grid via an amplifier, an enlarged sample image related to the sample surface is displayed on the cathode ray tube surface.

The enlarged sample image obtained in this way usually has the same horizontal (X-axis) and vertical (Y-axis) magnification; for example, a fixed square section on the sample surface is scanned with an electron beam. When the image of the section is enlarged and displayed on a cathode ray tube screen, a square-shaped enlarged image of the sample can be observed.

However, when the sample is a cross section of a film-like sample or a narrow, long and narrow sample such as the groove of a record, the sample must be moved in the longitudinal direction many times during observation, which requires troublesome operations. It had been.

The present invention has been developed in view of the above points.The electron beam is irradiated onto a sample in a narrowly focused state, and the electron beam irradiation position on the sample is two-dimensionally scanned by an electron beam deflection means. In a scanning electron microscope that detects an information signal generated from a sample and introduces the detected signal into an image display means that scans in synchronization with the sample scan to display a sample image, horizontal and vertical directions of the image display means are The scanning electron microscope is characterized by being provided with means for changing the ratio of the electron beam scanning widths in the horizontal direction and the vertical direction on the sample while the ratio of the electron beam scanning widths is fixed.

The present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic structural diagram showing an embodiment of an apparatus in which the present invention is applied to a scanning electron microscope. In the figure, reference numeral 1 denotes an electron gun for irradiating a sample 2 with an electron beam 3, and the electron beam 3 is narrowly focused onto the sample 2 by a focusing lens 4. For example, secondary electrons 5 generated from the sample 2 are detected by a detector 6, and the detection signal is applied to a brightness modulation electrode of a cathode ray tube 8 via an amplifier 7. Further, sawtooth scanning signals (currents) in the horizontal and vertical directions are supplied from the scanning signal generation circuit 10 to the horizontal deflection coil 9X and vertical deflection coil 9Y of the cathode ray tube 8, and the ratio of the amplitudes (peak values) of the signals is the same as that of the cathode ray tube. It is set to the same aspect ratio as the screen. 11 is an aspect ratio setting circuit that can independently change the amplitude of the horizontal or vertical scanning signal, and when a horizontal and vertical ratio variable knob (not shown) is operated, the peak value of the horizontal or vertical scanning signal is 1, ×1/2, ×1/3, ×1/4, and ×1/5, and in normal image observation, both are set to ×1. Reference numeral 12 denotes a reference magnification circuit. The reference magnification circuit 12 is a circuit for amplifying input horizontal and vertical scanning signals with the same amplification factor (current), and the normal image magnification is the amplification factor. It can be switched by changing .

In the apparatus configured as described above, horizontal scanning signals and vertical scanning signals from the scanning signal generating circuit 10 are input to the aspect ratio setting circuit 11 and the horizontal deflection coil 9X and vertical deflection coil 9Y of the cathode ray tube 8. When the amplification factors for the horizontal and vertical scanning signals in the aspect ratio setting circuit 11 are set to x1 by the operation knobs, the scanning signals from the scanning signal generation circuit 10 are directly transferred to the reference magnification circuit. 12, the reference magnification circuit 12 controls the electron beam deflection coils 13X and 13Y to scan the sample 2 with a scanning width corresponding to the sample enlargement magnification. Also, the horizontal deflection coil 9 of the cathode ray tube 8
Since the scanning signal from the scanning signal generation circuit 10 is supplied to the X and vertical deflection coils 9Y, the secondary electrons 5 generated from the sample 2 are transmitted to the detector 6.
When detected by the amplifier 7 and applied to the brightness modulation electrode of the cathode ray tube 8, a secondary electron image of the sample 2 is displayed on the screen of the cathode ray tube 8, and in this case, the magnification in the horizontal and vertical directions is Same magnification,
For example, it is displayed as shown in FIG. However, if the operation knob of the aspect ratio setting circuit 11 is set to x1 for the horizontal scanning signal and x1/2 for the vertical scanning signal, the scanning signal will not be generated. The scanning signal from the circuit 10 is input to the reference magnification circuit 12 as it is in the horizontal (X-axis) direction by the aspect ratio setting circuit 11.
In the vertical (Y-axis) direction, the amplitude is changed and input to the reference magnification circuit 12. Reference magnification circuit 12
is amplified by the same amplification factor specified in the magnification setting operation for both the input horizontal direction scanning signal and the vertical direction scanning signal, and then the deflection coil 13
Supply to X, 13Y. As a result, the aspect ratio of the electron beam operation area on the sample surface is different from the aspect ratio of the cathode ray tube screen. Therefore, if the secondary electrons generated from the sample 2 in this state are input to the cathode ray tube 8 in the same manner as described above, a secondary electron image of the sample 2 will be displayed on the screen of the cathode ray tube 8, but in this case, the horizontal direction The sample magnification magnification is displayed at the sample magnification specified by the reference magnification circuit 12, whereas the vertical sample magnification is displayed at twice the horizontal sample magnification; It will be displayed as follows. Therefore, for example, with the conventional device, when the magnification is set to low, the field of view of the sample is displayed only as a horizontal strip on the CRT screen, but with the device of the present invention, it is possible to display the sample so that it fills the CRT surface. In a single observation, a precise image can be observed over a wide range in the longitudinal direction.
It becomes possible to significantly reduce the number of times the sample is moved.

As described above, in the present invention, there is a means for changing the ratio of the horizontal and vertical electron beam scanning widths on the sample while the ratio of the horizontal and vertical electron beam scanning widths in the image display means is fixed. , it becomes possible to quickly and easily observe and measure a sample that would otherwise be displayed in a band-like manner.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the configuration of an embodiment of the present invention, and FIGS. 2 and 3 are diagrams for explaining the present invention. 1: Electron gun, 2: Sample, 3: Electron beam, 4: Focusing lens, 5: Secondary electron, 6: Detector, 7: Amplifier, 8: Braun tube, 9X: Horizontal deflection coil, 9
Y: Vertical deflection coil, 10: Scanning signal generation circuit,
11: Aspect ratio setting circuit, 12: Reference magnification circuit, 1
3X, 13Y: Electron beam deflection coil.

Claims (1)

[Scope of utility model registration request] A sample is irradiated with a narrowly focused electron beam, the electron beam irradiation position on the sample is two-dimensionally scanned by an electron beam deflection means, and an information signal from the sample generated by the electron beam irradiation is detected. In a scanning electron microscope in which a sample image is displayed by introducing a signal into an image display means that scans in synchronization with the sample scan, a sample image is displayed on the sample while the ratio of horizontal and vertical electron beam scanning widths in the image display means is fixed. 1. A scanning electron microscope characterized by comprising means for changing the ratio of horizontal and vertical electron beam scanning widths in the scanning electron microscope.